It is often necessary to adjust the gain of an electrical circuit to compensate for an input signal that varies in intensity. Typically, the gain control signal is linearly related to the gain of the circuit. However, in some circumstances, an exponential relationship between the control signal and the gain of the circuit may be required. For example, an exponential relationship may be necessary if the gain circuit is to be used to create a linear change in a signal representing a decibel level. In such a circuit, the gain of the circuit should be approximately exponential in relationship to the control signal.
Existing systems and methods for controlling the gain of a gain circuit typically use a single-ended control signal. Furthermore, such existing systems and methods typically are used in conjunction with a gain circuit having a single-ended input and a single-ended output. The output of such existing systems and methods may vary with changes in temperature.